Let grdcontour -N support the oneliner syntax #3702
                
     Merged
            
            
          
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THe problem is that grdcontour -N calls grdview and then itself via GMT_Call_Module. However, we have already flagged it as a oneliner but now there are several calls. The solution was to not trigger the oneliner check for grdcontour -N and then detect it instead in the special -N branch in grdcontour. We parse the options and discover if the command was a oneliner or not, and if it is we craft the gmt begin call needed and add the gmt end show call at the end. Seems to work.
Addresses aspects of #3701 but not the external part.